5.4 oil psi problem
 

I have a 2009 F-250 90,000 miles, lost oil psi, starts oil psi comes up but when engine gets to about 1500-1700 rpm it drops and light comes on, shut engine down and re start oil comes up same thing happens again, changed oil pump, timing chain adjusters and oil and filter no change. checked pick-up tube and installed a gage no difference oil psi still drops. any idea's?

Bad sending unit?

I have tried a mechanical gage and still no psi thank you

How did the cam phazers look. Did you see pieces of the timing chain guides or cam phazers in the pan..

I found some small pieces from the adjuster in the pan, the cam phazers have been bad for a wile, the hydraulic adjuster seals were blown out, thought that might be the problem. can't find anything wrong with the oil pump and still put a new one in. what I can't get through my little pea brain is why do I have good oil pressure at start up and when it gets to 1500-1700 RPM drops to zero. seems like a cavatasion problem or the oil is dumping over somewhere this all started on a - 30 winter day but this is the first time in 90.000 miles and we get a lot of -30-40 days up here. thank you for your help M.C.

I'm inclined to think that there is debris that is continuing to get sucked up on the pick up screen of the oil pump. Shut it off & it settles down & doesn't become a problem until it runs long enough to draw it back onto the pick up screen. In short you need to pull the oil pan & clean it. Then check oil flow to the heads

checking into that now, thank you and I'll let you know what we find. M.C.

God, I miss the days when you could climb under the hood, sit on the fender well, pull the head, lap the burnt valve and make your date that night. all with a pair of vice grips and a cold beer, I must be getin old thank you everybody for your help, I'll let you know how this turns out

That is my thought too, somewhere the ports are plugged up from the crap floating around in there, its kinda like when a gas tank is full of crap, it will run for a while until it sucks up the crap to the screen then quit but leave it sit for awhile and the stuff will settle to the bottom and it will start again until it happens again.